It's not like it's a good idea to just go on flashing "ok" signs and pretending it hasn't been coopted by facists
Why not? Symbols only have meaning given context. In Germany, a swastika is a symbol of hate, whereas in India it's a symbol of prosperity and good luck. It's usually not hard to differentiate them, so there's no real reason to avoid a symbol just because some idiots have decided to use it to mean something else.
On the flip side, there's a fantastic reason to keep using them: the best way to beat a troll/bully is to ignore them. Don't give them the emotional response they're looking for and you remove all rewards for their behavior.
So if the alt-right coopt a symbol, use it more. Don't let them impact you or they'll keep doing it.